Irregular Terrain Model (ITM)

The Irregular Terrain Model (ITM) estimates radio propagation losses for frequencies between 20 MHz and 20 GHz as a function of distance and the variability of the signal in time and space. It is an improved version of the Longley-Rice Model [1], which gives an algorithm developed for computer applications. The model is based on electromagnetic theory and signal loss variability expressions derived from extensive sets of measurements [2]. The ITM is applicable to point-to-area calculations. The "point" is where a broadcast station or a base station for mobile service may be located and "area" refers to locations of broadcast receivers or mobile stations. The ITM algorithm works in two modes: 1) area prediction mode - used when an exact terrain description is not available, and 2) point-to-point prediction mode - when terrain profile between the terminals is available.

Go to the MSAM Home Page.
Go to the OSM Home Page.
Go to the NTIA Home Page.
This page last updated March 20, 2002